From b22eb7cefb9d31cf862542f9cef90f97c0294842 Mon Sep 17 00:00:00 2001 From: "Paul E. McKenney" Date: Mon, 25 Nov 2019 14:33:28 -0800 Subject: [PATCH] torture: Hoist calls to lscpu to higher-level kvm.sh script On some kernels, concurrent calls to the lscpu command result in severe slowdowns. For example, on v4.16, a single lscpu invocation takes about two milliseconds, four concurrent invocations more than two seconds, and 16 concurrent invocations more than 20 seconds. Given that the only goal is to learn the number of CPUs, invoking lscpu but once suffices. This commit therefore invokes lscpu early in kvm.sh execution, setting the initial value of the TORTURE_ALLOTED_CPUS environment variable. Signed-off-by: Paul E. McKenney --- tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh | 7 +++---- tools/testing/selftests/rcutorture/bin/kvm.sh | 11 ++++++++--- 2 files changed, 11 insertions(+), 7 deletions(-) diff --git a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh index 1d98992..e035230 100755 --- a/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh +++ b/tools/testing/selftests/rcutorture/bin/kvm-test-1-run.sh @@ -133,11 +133,10 @@ fi qemu_args="-enable-kvm -nographic $qemu_args" cpu_count=`configNR_CPUS.sh $resdir/ConfigFragment` cpu_count=`configfrag_boot_cpus "$boot_args" "$config_template" "$cpu_count"` -vcpus=`identify_qemu_vcpus` -if test $cpu_count -gt $vcpus +if test "$cpu_count" -gt "$TORTURE_ALLOTED_CPUS" then - echo CPU count limited from $cpu_count to $vcpus | tee -a $resdir/Warnings - cpu_count=$vcpus + echo CPU count limited from $cpu_count to $TORTURE_ALLOTED_CPUS | tee -a $resdir/Warnings + cpu_count=$TORTURE_ALLOTED_CPUS fi qemu_args="`specify_qemu_cpus "$QEMU" "$qemu_args" "$cpu_count"`" diff --git a/tools/testing/selftests/rcutorture/bin/kvm.sh b/tools/testing/selftests/rcutorture/bin/kvm.sh index e19151c..78d18ab 100755 --- a/tools/testing/selftests/rcutorture/bin/kvm.sh +++ b/tools/testing/selftests/rcutorture/bin/kvm.sh @@ -24,7 +24,9 @@ dur=$((30*60)) dryrun="" KVM="`pwd`/tools/testing/selftests/rcutorture"; export KVM PATH=${KVM}/bin:$PATH; export PATH -TORTURE_ALLOTED_CPUS="" +. functions.sh + +TORTURE_ALLOTED_CPUS="`identify_qemu_vcpus`" TORTURE_DEFCONFIG=defconfig TORTURE_BOOT_IMAGE="" TORTURE_INITRD="$KVM/initrd"; export TORTURE_INITRD @@ -40,8 +42,6 @@ cpus=0 ds=`date +%Y.%m.%d-%H:%M:%S` jitter="-1" -. functions.sh - usage () { echo "Usage: $scriptname optional arguments:" echo " --bootargs kernel-boot-arguments" @@ -93,6 +93,11 @@ do checkarg --cpus "(number)" "$#" "$2" '^[0-9]*$' '^--' cpus=$2 TORTURE_ALLOTED_CPUS="$2" + max_cpus="`identify_qemu_vcpus`" + if test "$TORTURE_ALLOTED_CPUS" -gt "$max_cpus" + then + TORTURE_ALLOTED_CPUS=$max_cpus + fi shift ;; --datestamp) -- 2.7.4